Balers, for example, round balers, generally have a bale-forming chamber defined by a pair of opposing side walls associated with an array of side-by-side belts, transverse slats trained on chains, a plurality of rollers or a combination of these various elements, e.g., rollers and belts. During field operation, windrowed crop material, such as hay, is picked up from the ground and fed into a chamber of fixed or variable diameter. The hay is then rolled into a substantially cylindrical package, wrapped with twine, net or the like and ejected onto the ground for subsequent handling.
Because it is common for windrows of crop material to be uneven and typically narrower than the width of the bale-forming chamber, it is necessary for the operator of some prior art balers to observe the shape of the bale being formed and weave the baler in a generally zigzag pattern to uniformly distribute hay across the bale being formed and thereby avoid poorly shaped bales. This approach relies on the experience of the operator to determine when to laterally shift the position of the baler. The lack of exactness, inability to observe the bale shape, reliance on operator skill and operator fatigue each contribute to the possibility of improper feeding of crop material, causing misshaped bales.
In bales formed in belt type balers, when a substantially uniform diameter is not maintained, improper tracking can occur, resulting in belt jamming and damage to the baler. In addition, the uneven shape of the bale causes low density areas on the bale periphery, typically along one end of the bale, which could result in premature deterioration of the bale during field storage. That is, where the bale is exposed to weather extremes, the low density area does not shed water as well as an evenly balanced and uniformly compacted area.
In order to achieve substantially cylindrical bales, current balers use systems that employ mechanical sensors, which measure the amount of crop at the end regions of the bale, and then indicate to the operator the approximate density along the end regions of the bale. While mechanical systems are functionally acceptable, the mechanical linkages used to measure the density contain a large number of components, many of which are maintained in contact with either belts or the bale surface. As a result, the durability of the components and resultant reliability of these systems are reduced.
What is needed is a baler that includes components which operate in a non-contacting manner to calculate the density along the edge regions of the bale in order to monitor the cylindrical profile of the bale.